This changeset fixes a huge pile of problems, as indicated in the
error log of the Doxygen run after merging all the recent Doxygen improvements
unfortunately, auto-linking does still not work at various places.
There is no clear indication what might be the problem.
Possibly the rather unstable Sqlite support in this Doxygen version
is the cause. Anyway, needs to be investigated further.
this was introduced into namespace mobject and spread from there.
Since the habit is to use more specific typedefs like PClip,
it is preferrable to spell out the full namespace
